The present invention relates to a novel ester derivative of a substituted acetic acid having an excellent pharmacological activity and the process for preparing the same.
Hitherto, indomethacin (hereinafter referred to as IM) and diclofenac (hereinafter referred to as DF) have been broadly used as an acid nonsteroidal anti-inflammatory drug for a clinical use. IM and DF have a strong anti-inflammatory action, and are regarded as a first choice drug among other nonsteroidal anti-inflammatory drugs when used as an antirheumatic drug. However, both IM and DF have unfavorable side effects, for instance, a gastrointestinal disorder such as a loss of appetite, a nausea, a vomiting, a stomachache or an ulcer; and the like. Further, as for IM, it has another unfavorable side effects, for instance, a central nervous disturbance such as a headache, a sleepiness or a giddiness; and the like. Therefore, they are used restrictedly from the clinical viewpoint in spite of their strong therapeutic effect. Consequently, in case that IM or DF is administered to a rheumatic patient in need of a continuous IM- or DF-administration for a long period, especially a patient having a gastrointestinal disorder or a central nervous disturbance, there is a possibility that a use or an administration of IM or DF cannot but be limited or stopped from the reason described above. Moreover, its use or administration to the physical weak such as the aged or an infant is also restricted owing to its strong side effects.
As mentioned above, with respect to an acid nonsteroidal anti-inflammatory drug, there is a serious problem that it has a disadvantageous side effect such as a gastrointestinal disorder or a central nervous disturbance. Consequently, it is desired that an anti-inflammatory drug having an excellent pharmacological activity and reduced side effects is developed.
It is an object of the present invention to prepare an anti-inflammatory drug, which exhibits rapidly a pharmacological activity in man and maintains the activity for a long time, having a reduced side effect, e.g. a gastrointestinal disorder or a central nervous disturbance that is a drawback of a conventional acid nonsteroidal anti-inflammatory drug and, therefore, a wide safety margin.
Another object of the invention is to provide a process for preparing the above-mentioned drug.
These and other objects of the present invention will become apparent from the description hereinafter.